Aromatic azide material and process for producing color images

ABSTRACT

A LIGHT SENSITIVE MATERIAL CONTAINING A HARDENABLE HYDROPHILIC COLLOID, E.G., A GELATIN, LAYER WHICH CONTAINS A LIGHT SENSITIVE AROMATIC AZIDE AND A TRANSFERABLE DYE, AND PROCEDURE FOR UTILIZING SUCH MATERIAL, WHICH INCLUDES THE STEPS OF EXPOSING SAID COLLOID LAYER TO LIGHT UNDER A PATTERN OR NEGATIVE, TO HARDEN THE COLLOID IN PROPORTION TO THE DEGREE OF EXPOSURE, TEMPORARILY IMMOBILIZING THE TRANSFERABLE DYE, E.G., BY LOWERING THE PH OF THE COLLOID LAYER, OR BY SALT FORMATION, AND REMOVING THE UNHARDENED COLLOID BY DISSOLUTION WITH WATER, THEREBY PRODUCING A DYED MATRIX WITHOUT THE LOSS OF DYE DENSITY OF SAID TRANSFERABLE DYE DURING THE OPERATION WHICH REMOVES THE UNHARDENED COLLOID, THE IMMOBILIZED DYE BEING RENDERED TRANSFERABLE TO A RECEIVING LAYER OR BLANK, E.G., BY CONTACTING THE HARDENED RELIEF IMAGE WITH SUCH RECEIVING LAYER AT A HIGHER PH SUCH AS AN ALKALINE PH, E.G., ABOUT 8.

United States Patent Office 3,598,586 Patented Aug. 10, 1971 AROMATIC AZIDE MATERIAL AND PROCESS FOR PRODUCING COLOR IMAGES Bela Gaspar, 240 S. Oakhurst Drive, Beverly Hills, Calif. 90212 No Drawing. Filed July 26, 1967, Ser. No. 656,020 Int. Cl. G03c 5/00 US. Cl. 96-363 20 Claims ABSTRACT OF THE DISCLOSURE A light sensitive material containing a hardenable hydrophilic colloid, e.g., gelatin, layer which contains a light sensitive aromatic azide and a transferable dye, and procedure for utilizing such material, which includes the steps of exposing said colloid layer to light under a pattern or negative, to harden the colloid in proportion to the degree of exposure, temporarily immobilim'ng the transferable dye, e.g., by lowering the pH of the colloid layer, or by salt formation, and removing the unhardened colloid by dissolution with water, thereby producing a dyed matrix without the loss of dye density of said transferable dye during the operation which removes the unhardened colloid, the immobilized dye being rendered transferable to a receiving layer or blank, e.g., by contacting the hardened relief image with such receiving layer at a higher pH such as an alkaline pH, e.g., about 8.

The present invention relates to a material and process for the production of colored relief images.

The conventional dye transfer process, which is over half a century old, is capable of producing color photographic images of high quality. The dye transfer process is also being used for the manufacture of motion picture color film. Dye transfer images are valued for their photographic quality. This process is known as the imbibition process or dye transfer process. Such process involves producing a relief image by light exposure in a hardenable colloid such as gelatin and the like, and subsequent to removal of the unexposed unhardened portions of the colloid and the finishing of the relief image, treating the selectively hardened colloid relief image with a water-soluble dye to the desired dye density for the purpose of producing a color image.

The process consists of several steps, chiefly for producing color separation negatives and the manufacture of matrices from those separation negatives. The matrices are made on a silver halide material with a tanning developer, or by treating a developed image with a hardening bleach. These matrices, as is well known in the art, following development, are dyed with a transferable dye and the dye is transferred to a receiving layer on a film or paper, sometimes referred to in the art as a blank.

There are a variety of processes described in the prior art as dye transfer methods. They have one common feature: that is, a hydrophilic colloid is dyed with a water soluble dye and later transferred to a receiving sheet. The process most often used in practice consists of making hardened gelatine relief images and subsequently dyeing such reliefs to a certain dye density by controlling the degree of dye uptake by various methods, such as repeated checking or transfer tests, or other control methods which are not automatic and require great expenditure of time and effort by a trained operator. The transferable dyes must efficiently dye the hardened gelatin and must possess a certain rate of diffusion both into and out of the gelatin to transfer easily and completely into a receiving layer. There is no set rule in the prior art for the selection of suitable dyes for the dye transfer process and the choice of dyes is quite limited. By tedious, empirical testing, a limited number of acid dyes are claimed to be suitable, e.g., as noted in PB. Report 15790, p. 146.

As is well known in the art, the various steps of the conventional dye transfer process noted above require very careful controls which are cumbersome, critical, and time consuming. The process particularly becomes difficult to control from the stage after the color sepa ration negatives are made. The imbibition or dye transfer process, as is well known in motion picture production, is only economical when a system of 'very carefully established controls is established, and where from the same matrix, multiple transfer prints can be made by repeated dyeing up of the matrices and repeated transfers to a blank film. In this manner the cost of a single matrix and the establishment of elaborate controls is distributed over a number of dye transfers made from a single matrix, and thus the cost of a single print is only a fraction of the total cost. A similar situation exists where a number of color dye transfer still prints are made from one set of matrices. Here again the cost of the individual print is a fraction of the total.

However, if only one or two dye transfer prints are required, as in the case of high quality color prints which are in demand for industrial, artistic or other color photographic purposes, the cost of such single color prints becomes very high because of the cumbersome, time-consuming nature of the conventional dye transfer process. Thus a substantial demand exists for a dye transfer material and a simplified and economical procedure employing said material for producing such color prints. The present invention provides a material and method for production of dye transfer matrices and dye transfer images without the multiple steps of first making a relief image and then dyeing the relief image to a controlled density. The invention also eliminates the preparation and handling of dye solutions for this purpose, with all the inherent inconvenience and danger of spillage.

Further, for many purposes of color photography, for instance for the production of color separation images such as composite multicolor transparencies to be viewed in transmitted light, or for the purpose of color proofing material in the graphic arts field to be used as overlays and to be viewed by reflected light, a color photographic reproduction material is needed which has advantages over the presently used materials, which is-simple to manufacture and to process, and which can serve a multiplicity of uses.

It is well-known that soluble and transferable dyes have a considerable tendency to wash out of the colloid, e.g., gelatin, both from the hardened as Well as from the unhardened colloid areas. This is particularly the case at a temperature which is close to or higher than the melting point of the unhardened gelatin. Thus, after the colloid layer is selectively hardened by exposure, it is generally subjected to a treatment with hot water or a mixture of aqueous solvents at a temperature about the meltingpoint of the colloid, in order to produce the relief image through the removal of the unhardened colloid. Such temperature is close to or higher than the melting point of the colloid, which in the case of gelatin is about 30 to about 35 C. It has been found that various dyes ranging from so-called acid to direct dyes, are washed out of the gelatin or like colloid in various degrees at such treatment temperatures. This is frequently the case with dyes which are desirable for the purpose of producing dye transfer images, and particularly in dyes which contain salt-forming groups such as sulfonic or carboxylic acid groups. Accordingly, heretofore, to applicants knowledge, pre-dyed light sensitive dye transfer materials for producing pre-dyed relief images have not been produced.

The present invention provides pro-dyed light sensitive materials and processes utilizing same which are suitable for the production of colored relief images, and which overcome the above disadvantages. This is accomplished according to the invention by immobilizing the transferable dye, that is, making the dye incapable of being washed out of the colloid layer, during the step of treatment of the exposed colloid with warm or hot water at a temperature approximately the melting point of the colloid, or a suitably higher temperature, to produce the dyed relief image. It was indeed surprising that a dye image can thus be produced in the hardened colloid portions while retaining substantially the full maximum dye density at the point of highest exposure, since as previously noted, transferable dyes are washed out in various degrees from dyed colloid layers at temperatures of approximately the melting point of the colloid.

The present invention involves the production of a material which contains a transferable dye in a predetermined concentration, in combination with a sensitizer, in a hardenable colloid such as gelatin, glue, polyvinyl alcohol, cellulose ethers and the like, and by immobilizing the transferable dye prior to removal of the unhardened portions of the matrix, permits in a single step production of a dye transfer matrix ready to be transferred to a receiving layer without any further operations. This single step comprises, following exposure of the matrix to light, dissolving the unexposed unhardened portions of the matrix without removing the immobilized transferable dye from the exposed hardened portions. Without immobilizing the transferable dye prior to removal of the unhardened colloid portions according to the invention, the hardened portions of the material would lose all or a substantial portion of the dye density originally present in such portions of the layer.

Thus, the present invention dispenses with the prior art cumbersome and difiiculty controllable dyeing step of the finished colloid relief, achieving substantial economy in time and labor, improving uniformity in quality of the finished product, and facilitating production of a material and process which can be used to produce either dye transfer images or color separation images.

The marked simplicity of the process of the present invention in contrast to the conventional method of making dye transfer matrices, is apparent when compared with the processing instructions of the well known Kodak Dye Transfer process, which specifies that seven trays are needed for the working solutions for dyeing the matrices. Applicant is aware of no process and material heretofore available for making a light sensitive material pre-dyed with a transferable dye, which permits the one step removal of the unhardened colloid layer after light exposure, and without impairing the dye density of the hardened portions of the matrix, such dye density being substantially in proportion to the amount of exposure and hardening.

The dye transfer material of the invention can be utilized for a dual purpose, that is, for the production of pre-dyed matrices for making dye transfer images, or for the production of transparency materials. The material of the invention can be employed to produce, in addition to half-tone color images, also continuous-tone color images hitherto not obtainable with the presently available color-proofing material. It is noted in this respect that Graphic Arts Monthly, March 1967, page 74, states: At the present time there is no satisfactory means of proofing continuous-tone separations. Presenty available color films have too high a contrast for this use and the colors available do not match graphic arts colors.

Briefly, according to the invention, there is provided a light sensitive material comprising a support having a hardenable hydrophilic colloid coating containing a transferable dye capable of being temporarily immobilized in said colloid, and a light sensitive aromatic azide. Such light sensitive layer thus is uniformly pre-dyed with the transferable dye.

The material of the present invention thus comprises a hardenable hydrophilic colloid such as gelatin, glue, polyvinyl alcohol, hydroxyethyl cellulose and the like, forming the matrix. The colloid contains as light sensitizer a light sensitive aromatic azide which preferably has water solubilizing groups such as sulfonic or carboxylic acid groups or their corresponding alkali metal salts. Generally, such azide is employed in amounts ranging from about 0.2 to about 10 grams per grams of colloid. In addition to the sensitizer, the colloid contains a transferable preferably water-soluble dye, incorporated in pre-. determined quantity into the colloid, e.g., in amounts ranging from about 0.20 to about 10 grams per 100 grams of colloid.

There is also provided according to the invention a method for producing a dyed relief image suitable for dye transfer, employing the pre-dyed material, described above, which comprises exposing predetermined portions of the above-pre-dyed light sensitive material of the invention to light, to cause the aromatic azide so exposed to light to harden the hydrophilic colloid selectively or differentially in such predetermined exposed portion in proportion to the degree of light exposure, temporarily immobilizing said transferable dye, treating the hydrophilic colloid with an aqueous solution, preferably at elevated temperatures, and removing the unhardened colloid substantially without removal of said immobilized transferable dye from the hardened portions of the col loid and forming a dyed relief image which retains the initial dye density in proportion to the amount of remaining hardened colloid. The dyed relief image can then be contacted with a suitable receiving layer under conditions to cause transfer of the temporarily immobilized transferable dye into the receiving layer.

The dyed relief image can be utilized per se as a transparency, or the so-produced dyed relief image can be utilized as a dye transfer matrix, whereby the transferable dye is again rendered mobile and is diffused over into a receiving layer, which can be in the form of a colloid blank, e.g., gelatin and the like. In the former case, the dye can remain permanently immobilized, and in the latter case, the transferable dye is maintained only temporarily immobilized until the dyed relief image is brought into contact with a receiving layer or substrate. The immobilization of the dye can be effected at any point before the dyed relief image is produced, that is, at any point prior to treatment of the exposed colloid layer for removal of the unhardened portions thereof.

According to one mode of procedure, such immobilization of the dye, depending on the solubility thereof, can be eifectedby changing the pH of the material at any stage prior to dissolving the unhardened portions, particularly by lowering the pH of the material from e.g., neutral, i.e., around 7, down to between about 6 and about 2, depending upon the nature of the dye, e.g., by treatment of the material with a suitable aqueous acid solution such as dilute acetic acid, hydrochloric acid, and the like.

It is thus possible, by changing the pH of the light sensitive material, to control the solubility of the dye within relatively wide ranges, thus providing a wide selection of transferable dyes for use according to the invention.

Another mode of procedure for immobilizing or preventing the removal of a transferable dye from the dyed relief image is to produce at any point prior to removal of the unhardened colloid, a salt of the dye, which is either insoluble or substantially insoluble in water. This can be accomplished by treatment of the material prior to removal of the unhardened colloid, with inorganic cations such as calcium, strontium, barium, magnesium, zinc, cadmium, and the like, or with a nitrogenous base or an amine, preferably one of moderate basicity and which is not more basic than ammonia or pyridine, and thus a pK higher than 4.75. Suitable nitrogenous base compounds or amines for the production of the immobilized dye salt are the primary, secondary or tertiary aliphatic, aromatic or heterocyclic amines, which produce temporary insolubilization of transferable dyes containing salt-forming anions. Examples of these bases are cyclohexylamine, alkyl-substituted cyclohexylamines such as the methyl and ethyl derivatives, pyridine, polyvinyl pyridine, diphenyl guanidine, and the like. The inorganic cation or nitrogenous base employed for temporary immobilization of the transferrable dye should be capable of releasing the insoluble salt of the dye upon suitable treatment, as described below.

The a bove-noted lowering of pH or the salt formation for temporarily immobilizing the soluble transferable dye can be accomplished by separate treatment of the coated light sensitive material, e.g. in a separate bath prior to or subsequent to exposure of the material, and prior to treatment, as with Warm water, for removal of unhardened colloid. Alternatively, such immobilization can be effected by suitable treatment of the coating colloid prior to applying such composition to a support for the production of the coated material.

The removal of the unhardened colloid following exposure to light is accomplished conveniently in water of elevated temperature. For example, if gelatin is used, the material is treated at 30 C. or higher. However, colloids can be employed which do not require warm water treatment but which can be treated with water at ambient temperature, such as polyvinyl alcohol of low degree of polymerization, methyl cellulose or carboxymethyl cellulose. If desired, although not necessary, solvents such as lower alcohols, e.g., methanol, or alkali carbonate or hydroxide can be used with cellulose or gelatin derivatives containing salt-forming groups.

In order to solubilizer or permit mobility of the immobilized dye for transfer of the dyed relief image to a receiving layer, where the immobilized dye is formed by a reduction in pH of the material or by salt formation employing a nitrogenous base, the transferable dye can be solubilized to any desired degree by simply changing the pH, e.g., from about neutral to highly alkaline, e.g., to pH of from above 7 to about 12. Where the immobilized dye was formed by salt formation employing an inorganic cation, such as calcium, such dye can be solubilized by decomposing the insoluble salt, e.g., by double decomposition with an agent containing a solubilizing anion, such as the sulfate ion. Thus, the immobilized calcium salt form of a transferable dye can be solubilized by contacting the dyed relief image containing said immobilized dye with sodium sulfate or sulfuric acid. Further, where the dye was immobilized by reduction in pH of the material, the receiving layer can contain a strong non-diffusing organic, e.g., quaternary nitrogenous, base such as poly-2vinyl pyridinium l-methyl-metho-sulfate, causing mobility and migration of the transferable dye by forming an insoluble complex with the transferable dye in the receiving layer.

The combination of transferable and preferable watersoluble dyes with light sensitive azides in a hardenable colloid layer according to the invention is particularly advantageous and affords a substantial economy in manufacture and processing. The light sensitive azides are nonreactive with respect to the transferable dyes and are completely compatible therewith. Such combination of azides with transferable dyes provides a highly stable combination even at low pH, with no interaction of the compo nents occurring, thus affording wide freedom of conditions which are compatible with the optimum choice of dyes and sensitizer concentration.

The dyes employed herein for producing the dyed relief images and termed herein transferable dyes can be present in the hardenable colloid in a water soluble or water insoluble form, provided they are transferable, or can be rendered transferable by suitable treatment as described above. This permits a wide selection of dyes for purposes of the invention. Such dyes are generally anionic and can be free acids, water soluble salts or Water insoluble salts, as long as they can be converted into a transferable form after the formation of the hardened relief image for transfer of the dye to a receiving layer, as will become more apparent hereinafter, and in the following examples. I

According to one mode of characterization of suitable dyes for use in the invention, the transferable dye is of a type which when present in a colloid layer or in a dved relief image, and such layer is contacted with a receiving layer at a pH of at least 8, i.e., about 8 or higher, the dye commences to transfer to the receiving layer. The rate of transfer depends on various factors, such as solubility of the dye, nature of the blank, temperature of treatment, and other factors.

Thus, since the present invention utilizes a transferable dye which is initially incorporated in the colloid layer, and is therefore present both in the hardened and unhardened colloid portions, any transferable dye can be employed which can be homogeneously incorporated into the colloid, e.g., gelatin or the like, in a predetermined concentration, without the requirement of being able to selectively dye the hardened or unhardened portions. of the image according to prior art procedures. The transferable dyes employed in the material and process of the present invention therefore are not limited, for instance, by their rate of diffusion into the hardened relief image, since thye are already present in the light sensitive material before the hardened relief image is formed, and their diffusion out of the colloid or gelatin of the relief image is controlled by the various means described above. Hence, the dyes suitable for the material and process of the invention are not characterized by the many complex requirements and limitations of dyes employed in conventional dye-transfer and imbibition processes.

Examples of classes of anionic transferable dyes which can be employed according to the invention are those selected from the group consisting of azo dyes, including monoazo and disazo dyes, anthraquinone, oxazine, xanthene and phthalocyanine dyes. The phthalocyanine dyes can be in the form of their copper, nickel or cobalt complexes. These dyes are preferably Water soluble and are preferably in the form of salts containing at least one, e.g., one or more, solubilizing groups such as sulfonic, carboxylic, or other like groups, in the free acid form or as alkali metal salts. Thus, for example, the phthalo cyanine dyes can contain one or more sulfonic or carboxylic acid groups, e.g., as the sodium salts. The dyes and dye salts however can be converted to a Water insoluble form, as noted above, for immobilizing the dye, and which is later convertible as desired to a mobile form.

Specific examples of transferable dyes which can be employed according to the invention are set forth below. The dyes are identified by specifying the general type or dye class and including their Color Index number. The dyes are generally identified in the conventional way, as used in the Color Index, e.g., Color Index, 2nd Edition 1956, vol. 3, page 3009, or alternatively by the scheme of the dye formation. As an illustration, the dye obtained by coupling diazosulfanilic acid with beta naphthol is identified as diazo sulfanilic acidbeta naphthol.

MAGENTA DYES The aromatic light sensitive azides employed in producing the light sensitive material of the invention can Color index number Color index type Dye type Dye 18133 0.1. Acid Red 264.- Monoazo Anisidine N-p-tolylsulfonyl H-acid.

The same type of dye but containi 45190 0.1. AcidViolettL- Xanthene 68205 0.1. Acid Red 82..

YELLOW DYES additional sulfo group in the 3 position of the phenyl group. 18050 0.1. Acid Red 1. Monoazo Aniline- N-acetyl H-acid.

The same type of dye as in 3, containing one additional sulio group in the 4 position of the phenyl group. The same type of dye as in 3, containing two additional sulfo groups in the 2,4 positions.

18134 Acid Red 249 Monoazo -chloro-2-phenoxyaniline-eN-p-tolysulfonyl H-acid.

Same type as in 6, containing an additional sulfo group in the 4 position. 18130 Acid Red 155 Monoazo 4-cyclohexyl-o-toluidine N-p-tolylsulfonyl H-acid. 29100 Direct Red 31 Disazo Aniline (2 mol) 6,6-imino-bis-1-naphthol-3-sulfonlc acid. 29065 Direct Red 79 do. By phosgenation of o-p-tolylsulfonyl H-acidcresidine. 28165 Direct Red 108 do 4-arn i1o-5chloro-ru-toluenesulfonic acido-toluidine N-benzyol-J- aci 18035 0.1. Acid Red 161. Monoazo p-Oyclohexylanilinc- 2,5-dichlorobenz0yl K-acid. 18025 0.1. Acid Red 107. do 0-anisidine-+N-2,4-dichlorobenzoyl K-acid.

Same type as in 13 but containing an additional sulfo group in the 3 position of the phenyl group.

Byfcontdensation of o-toluidine with 3,6-dichlorofluorane and sulone 1011. 0.0. Acid Red 81- Anthraquinone- N-methyl anthropyridenc mono sulfonlc acid derivative.

Same as in 16, but disulfonated derivative Color index number Color index type Dye type Dye 1 19230 Monoazo 6-chloro-0t0luidlner3-carbethoxy-1-(6-chloro-4-sulfoo-tolyl)- B-pyrazolone. 2 24895 0.1. Direct Yellow 12.- Disazo Ohrysophenine. 3 25135 0.1. Acid Yellow 38 d0 fiflg-giiodimethanilic acid pheno1(2 mol) and ethylation of group. 18950 0.1. Acid Yellow 40... Monoazo N-toluenesulfoxy aminophenol phenyl-3-methyl-5-pyrazolone. 18890 0.1. Acid Yellow 34 ..do. Aniline- 1-(2-chloro-5-sulfo-phenyl)- 3-methyl-5-pyrazolone. 6 29000 0.1. Direct Yellow 44.. Disazo By phosgenation of equimolecular mixture of 2 monoazo dyes:

Meganilic acid o-anisidine, n-phenylenediaminesalicylic aci 7 29025 0.1. Direct Yellow ..do By phosgenation of 3'amino-1,S-naphthalene-disulfonic acid-9 m-toluidine.

Black dyes 20470 0.1. Acid Black 1. Disazo p-Nitroaniline (1) -(acid) aniline (2) (alk) H-acid. 27260 0.1. Acid Black 3 do 7-arrtninol,3naphthalcne disulfonic acid 1-naphthylamine -aci 27710 0.1. Direct Black 3 do Aniline- 1naphthyl amino- (alk)-gamma acid.

PHTHALOCYANINE DYES Color index number Color index type Dye type Dye 74180 Direct Blue 86 Sodium salt of disulfonated copper phthalocyanine. 74200 Direct Blue 87.. Sodium salt of trisulionated copper phthalocyanine. 74220 Sodium salt of tetrasulionated copper phthalocyanine. 74320 Tetraphenyl 3-tetracarboxy copper phthalocyanine. 63340 Anthraqumone Bis 1,5-(3su1io4-methylaminophenyl 4,8-dihydroxy anthra- The transferable dyes suitable for use in the present invention have the advantage that they can be incorporated from solution into the liquid coating colloid solution, or they can be added in admixture with the aromatic azide sensitizer in a single solution into the colloid immediately preceding coating on the support. The solution of transferable dye, when protected from light, is stable for an extended period of time, and the mixture of azide sensitizer and dye solution is stable and compatible. The process of manufacture of the light sensitive material is thus greatly simplified, and the stock solution of sensitizer and dye can be added in any desired predetermined quantity and ratio to the coating colloid. Thus, homogeneously predyed and presensitized materials of reproducible quality can be produced according to the invention.

quinone.

l-amino t(4-acetaminophenyl)anthraquinone sulfonic acid. 1-5-dihydroxy-4,-8-diamino-2,fi-disulionic acid.

be water soluble, such as mono-, bisand polyazides. Specific examples are the alkali salts of the following acids azido-S-naphthol 4-azido phenol 4,4-diazido-benzophenone 4,4',4-trisazido-triphenylmethane Various hydrophilic hardenable colloids can be employed in producing the light sensitive material containing a transferable dye and a light sensitive aromatic azide according to the invention. Examples of such hydrophilic colloids are gelatin, polyvinyl alcohol of various degrees of polymerization and viscosity, which can be partially esterified with acetyl groups or residues of any dior polybasic acid, methyl cellulose, ethyl cellulose, hydroyethyl cellulose, cellulose glycolic acid, cellulose hydroxyethyl derivative of methyl, ethyl, benzyl cellulose, polymeric hydrophilic acrylates such as polyacrylic acid, and copolymers of hydrophilic acrylic compounds. If desired, mixtures of such colloids can also be employed, such as a mixture of gelatin and polyvinyl alcohol.

The support or substrate to which the hardenable hydrophilic coating containing the transferable dye and light sensitive aromatic azide can be applied, can be opaque or transparent, and can be, for example, paper, a plate or a plastic film, e.g., a cellulose acetate, polyester or polystyrene film, and the like. The coating composition which is applied to the support can contain, for example, from about 0.5 to about 10 mg. or more of transferable dye per 100 square centimeters of coating.

The following are examples of practice of the invention:

EXAMPLE 1 0.25 gram of the sodium salt of disulfonated copper phthalocyanine C.I. No. 74180, Direct Blue 86 is incorporated in 100 cc. of gelatin solution containing 0.1 gram of 4,4-diazido stilbene-2,2'-disulfonate disodium salt. The above mixture 100 cc.) is coated on one square meter area of a subbed transparent polyester base. The pH of the gelatin is 6.2. The dried coating is exposed under a negative by exposure with a General Electric mercury sunlamp (275 watts, 110 volts) at a distance of 1 foot, for between about 5 and minutes.

The resulting exposed but otherwise untreated material is then treated in warm water at a temperature about the melting point of the gelatin (30-32" C.) and a relief image is produced. However, a certain portion of the dye is dissolved out of the relief image even at those places of excessive exposure. Thus, the maximum density of the dye image in the hardened portions, as compared to that of the untreated material in the same areas, is appreciably reduced depending on the time and temperature of the water treatment and on the quality of the gelatin.

EXAMPLE 2 The exposed material produced in Example 1 is treated according to the invention with 0.5 normal acetic acid solution for 3 to 5 minutes to temporarily immobilize the dye, and the material is then treated with water at temperatures between 30 to 32 C. In about five minutes the unhardened gelatin is washed away and a cyan dye relief image of high brilliancy and permanence, proportionate to the degree of hardening, is produced. The maximum density of such dye image is very close to that of the previously untreated material in the same areas.

EXAMPLE 3 The gelatin coating solution of Example 1 containing the phthalocyanine dye and diazide sensitizer, is buffered to a pH between 3.8 and 4.0 by addition of citiric acid buffer solution, before coating the material on the transparent base as described in Example 1. The coated material is then exposed as described in Example 1 and is then treated in warm water (3032 C.), removing unhardened gelatin, and a dyed cyan relief image without any appreciable loss of maximum dye density results.

EXAMPLE 4 The support or base containing the dyed relief image of Examples 2 and 3 can be utilized as such as a transparency or in an overlay or, such dyed relief image can be used in making a dye transfer image in the following manner: The

transfer is made onto a receiving layer which consists of a blank of hardened gelatin soaked in water for about 15 minutes. The slightly wet dyed relief image is brought into contact with the soaked receiving layer in which the excess Water and air bubbles are removed by squeegees or rollers, according to procedure well known in the art for producing dye transfer images. The pH of the receiving layer is adjusted to between about 8 and 9 by treatment thereof with ammonia solution, causing the temporarily immobilized transferable dye to be transferred to the receiving layer in a period of about 2 to about 10 minutes, producing a cyan dye image of good dye density in the receiving layer corresponding to the dyed relief image as to maximum dye density.

EXAMPLE 5 The procedure of Example 4 is repeated except that the receiving layer contains the non-diffusing strong organic base, poly-2-vinyl pyridinium l-methyl-metho-sulfate. Such base forms an insoluble complex in the receiving layer with the transferable dye, and substantially accelerates the rate of dye transfer.

EXAMPLE 6 The coating composition of Example 1 is used, but in which the salt of the disulfonated copper phthalocyanine is replaced by the same amount of the sodium salt of the trisulfonated copper phthalocyanine, CI. 74200 0.1. Direct Blue 87. To the coating solution there is also added 5 cc. of a 2% solution of polyvinyl pyridine hydrochloride. In carrying out the procedure of Example 1, this latter solution temporarily immobilizes the otherwise very soluble phthalocyanine dye to such a degree that the maximum density is not impaired in the warm water treatment for the production of the dyed relief image. Such immobilization of the dye does not impair the subsequent transferability of the dye which is carried out by employing a receiving layer having an alkaline pH of about 8.0 by treatment of such receiving layer with ammonia.

EXAMPLE 7 The procedure of Example 6 is followed except that the addition of the polymeric base salt is omitted and the coating solution is buffered to a pH of between 2.6 and 3.0 with 1% sulfamic acid solution, thus immobilizing the image dye during the washout step.

EXAMPLE 8 The coating solution of Example 6 is used but without the polyvinyl pyridine hydrochloride, and the coating material is exposed in the usual way through the transparent base. The resulting printed material is treated for from 1 to 3 minutes with an acid solution containing 3 to 5 cc. of 2 normal HCl per cc. water and thereafter Washed out in warm water as described above. The maximum dye density is preserved in the resulting relief image.

EXAMPLE 9 The exposed material of Example 8 is treated with a 1 to 2% solution of diphenyl guanidine acetate for several minutes to immobilize the phthalocyanine dye by salt formation. The unhardened colloid is subsequently washed out in Warm water to produce the dyed relief image. By this treatment the maximum dye density is preserved in the finished image, without impairing the subsequent transferability of the dye.

EXAMPLE 10 In the coating composition of Examples 6 to 9, the phthalocyanine dye therein in each case is replaced by the same amount of the more soluble sodium salt of tetrasulfonated copper phthalocyanine, CI. #74220. Further, the procedure of Examples 6 and 7 employing the latter dye is changed in that each of the coating solutions is buffered to a somewhat lower pH to insure temporary immobilization of this more soluble dye.

Thus, in Example 6, in which polyvinyl pyridine hydrochloride is added, the amount thereof is increased, and the coating solution is buffered to a pH of 3.0 or some- What less. In Example 7, the coating solution is buffered to a pH of 2.4, with hydrochloric acid solution.

In Examples 8 and 9, wherein the coating solution is not buffered but the dye is immobilized after exposure and before the washout step, the quantity of acid solution used for this purpose in Example 8 is increased slightly, and in Example 9 the diphenyl gu'anidine acetate is replaced by the corresponding hydrochloride salt, and to that solution, 3 to cc. of 2 normal HCl, per 100 cc. of solution is added.

If the coated material of Examples 6 to is not buffered or treated as described therein, to immobilize the phthalocyanine dye, and after exposure is treated with warm water for the production of a relief image, a substantial loss of dye density of about 50% or more results.

In each of Examples 2, 3, and 6 to 10, the dyed relief image can be utilized as such as a transparency or as an overlay material, or the dyed relief image can be used as a dye transfer matrix and the dye can be transferred to a receiving layer which contains the salt of a non-diffusing polymeric strong base, such as the methylmethosulfate of polyvinyl pyridine, which forms an insoluble non-diffusing complex of the transferred dye.

EXAMPLE 1 1 In place of the dye immobilizing procedures of Examples 2 to 10, the dyes of Examples 2 to 10 are incorporated into the coating solution in the form of a water insoluble salt of the respective dye by adding 10 cc. of a 2.5% solution of cyclohexylamine in alcohol or acetone. The resulting insoluble dye salts are changed into a transferable dye form after Washing out the unhardened relief image, by contacting the dyed relief image, with a receiving layer of a pH higher than 8.0.

EXAMPLE 12 The procedure of Example 2 is followed, but employing as the transferable dye tetraphenyl 3-tetracarboxy copper phtlralocyanine, or its alkali metal salt.

Results similar to those of Example 2 are obtained.

EXAMPLE 13 The procedure of Examples 2 to 4 is repeated, but employing in place of the phthalocyanine transferable dye therein, 0.2 to 0.5 gram per 100 cc. of 5% gelatin solution, of each of the respective dyes from the table set forth below.

Magenta dyes Color index number:

18134 Acid Red 249. 45190 Acid Violet 9'. 68200 Acid Red 81.

68205 Acid Red 82.

Yellow dyes Color index number:

Results similar to those of Examples 2 to 4 are obtained in each case.

12 EXAMPLE 14 The coating composition of Example 1 is made, but employing as the transferable dye 0.5 gram of the disazo dye, C.I. No. 25135, acid yellow 38. To the coating composition there is also added 0.5 g. calcium lactate; after the formation of the relief image the material is treated with a 0.2% sulfuric acid or alternatively with a 1% solution of sodium sulfate, in order to render the dye mobile when contacted with a receiving layer, as described in Example 4.

EXAMPLE 15 The procedure of Examples 2 to 4 is followed, except employing in place of the gelatin a 2-5% solution of hydroxyethyl cellulose, or a 25% solution of a mixture of gelatin and low viscosity polyvinyl alcohol.

Results similar to those of Examples 2 to 4 are obtained.

EXAMPLE 16 The procedure of Examples 2 to 10 is followed, except employing as the light sensitive azide between 0.2 and 0.5 gram of each of the respective following azides:

4-azido benzal pyruvic acid 4,4-diazido diphenyl-2,2'-disulfonic acid 4,3-diazido benzalacetone-Z-sulfonic acid azido-S-naphthol 4,4,4"-trisazido-triphenylmethane Although various modifications of my invention have been described for purposes of illustration, the invention is not to be taken as limited except by the scope of the appended claims.

I claim:

1. A method for producing a dyed relief image, which comprises exposing predetermined portions of a light sensitive material comprising a support having a hardenable hydrophilic colloid coating containing an anionic transferable dye in a predetermined dye density, and a light sensitive aromatic azide, to cause said hydrophilic colloid to harden in said predetermined exposed portions, temporarily immobilizing said transferable dye, treating the hydrophilic colloid with an aqueous solution and removing the unhardened colloid substantially without removal of said immobilized transferable dye from the hardened portions of said colloid and forming a dyed relief imake which retains the initial dye density substantially in proportion to the amount of exposure and remaining hardened colloid.

2. The mtthod as defined in claim 1, wherein said immobilizing said transferable dye is effected by changing the pH of said light sensitive material prior to said treatment with said aqueous solution.

3. The method as defined in claim 1, wherein said immobilizing said transferable dye is effected by reducing the pH of said light sensitive material with an acid solution to a pH of between about 6 and about 2 prior to said treatment with said aqueous solution.

4. The metheod as defined in claim 3, wherein said hydrophilic colloid containing said dye and said azide is initially provided with said pH of between about 6 and about 2.

5. The method as defined in claim 3, wherein said pH of said light sensitive material is reduced to said pH of between about 6 and about 2 by separately treating said colloid prior to treating same with said aqueous solution.

6. The method as defined in claim 1, wherein said immobilizing said transferable dye is elfected by converting said dye to a substantially water insoluble dye salt prior to said treatment with said aqueous solution.

7. The method of claim 6, wrerein said dye is treated with inorganic cations selected from the group consisting of calcium, strontium, barium, magnesium, zinc and cadmium, to convert said dye to said substantially water insoluble dye salt.

8. The method of claim 6, wherein said dye is treated with a nitrogenous base which is not more basic than ammonia or pyridine.

9. A method as defined in claim 1, wherein said dye is a transferable anionic dye selected from the group consisting of transferable azo, anthraquinone, oxazine, Xanthene and phthalocyanine dyes.

10. The method as defined in claim 1, and including contacting said dyed relief image with a receiving layer under conditions to cause transfer of said temporarily immobilized transferable dye into said receiving layer.

11. The method as defined in claim 3, and including contacting said dyed relief image with a receiving layer having a pH ranging from about neutral to highly alkaline.

12. The method as defined in claim 3, and including contacting said dyed relief image with a receiving layer containing a non-diffusing quaternary nitrogenous base.

13. The method as defined in claim 7, and including treating said dyed relief image with a solubilizing anion to convert said insoluble dye salt to a transferable form.

14. A light sensitive material which comprises a support having a hardenable hydrophilic colloid coating containing an anionic water-soluble transferable dye and a light sensitive aromatic azide.

15. A light sensitive material as defined in claim 14, buffered to a pH of between about 6 and about 2, and temporarily immobilizing said dye in said colloid.

16. A light sensitive material as defined in claim 14, wherein said transferable dye is of a type which when present in a dyed relief image and such image is contacted with a receiving layer at a pH of at least 8, said dye commences to transfer to said receiving layer.

17. A light sensitive material as defined in claim 14, wherein said dye is a transferable anionic dye selected from the group consisting of transferable azo, anthraquinone, oxazine, Xanthene and phthalocyanine dyes.

18. A light sensitive material as defined in claim 14, wherein said transferable dye is a water soluble phthalocyanine dye containing at least one water solubilizing group selected from the class consisting of sulfonic and carboxylic acid groups.

19. A light sensitive material as defined in claim 14, wherein said colloid is gelatin and said dye is a transferable anionic dye selected from the group consisting of transferable azo, anthraquinone, oxazine, Xanthene and phthalocyanine dyes, said dyes containing at least one solubilizing group.

20. A light sensitive material as defined in claim 14,

15 wherein said transferable dye consists of a salt of a transferable anionic dye and a nitrogenous organic base having a pH higher than 4.75.

References Cited UNITED STATES PATENTS 3,010,391 11/1961 Buskes et al. 96-75X 2,054,261 9/1936 Lierg 101-464 3,091,528 5/1963 Buskes 96-75 3,246,984 4/1966 Nagy et al. 9675 3,326,682 6/1967 Endermann et al. 9691 FOREIGN PATENTS 883,557 11/1961 Great Britain 101149.5

NORMAN G. TORCHIN, Primary Examiner J. R. HIGHTOWER, Assistant Examiner U.S. Cl. X.R. 

